Gas-dynamic shock heating of post-flare loops due to retraction following localized, impulsive reconnection

We present a novel model in which shortening of a magnetic flux tube following localized, three-dimensional reconnection generates strong gas-dynamic shocks around its apex. The shortening releases magnetic energy by progressing away from the reconnection site at the Alfven speed. This launches inward flows along the field lines whose collision creates a pair of gas-dynamic shocks. The shocks raise both the mass density and temperature inside the newly shortened flux tube. Reconnecting field lines whose initial directions differ by more that 100 degrees can produce a concentrated knot of plasma hotter that 20 MK, consistent with observations. In spite of these high temperatures, the shocks convert less than 10% of the liberated magnetic energy into heat - the rest remains as kinetic energy of bulk motion. These gas-dynamic shocks arise only when the reconnection is impulsive and localized in all three dimensions; they are distinct from the slow magnetosonic shocks of the Petschek steady-state reconnection model

On Flux Rope Stability and Atmospheric Stratification in Models of Coronal Mass Ejections Triggered by Flux Emergence

Flux emergence is widely recognized to play an important role in the initiation of coronal mass ejections. The Chen-Shibata (2000) model, which addresses the connection between emerging flux and flux rope eruptions, can be implemented numerically to study how emerging flux through the photosphere can impact the eruption of a pre-existing coronal flux rope. The model's sensitivity to the initial conditions and reconnection micro-physics is investigated with a parameter study. In particular, we aim to understand the stability of the coronal flux rope in the context of X-point collapse and the effects of boundary driving in both unstratified and stratified atmospheres. In the absence of driving, we assess the behavior of waves in the vicinity of the X-point. With boundary driving applied, we study the effects of reconnection micro-physics and atmospheric stratification on the eruption. We find that the Chen-Shibata equilibrium can be unstable to an X-point collapse even in the absence of driving due to wave accumulation at the X-point. However, the equilibrium can be stabilized by reducing the compressibility of the plasma, which allows small-amplitude waves to pass through the X-point without accumulation. Simulations with the photospheric boundary driving evaluate the impact of reconnection micro-physics and atmospheric stratification on the resulting dynamics: we show the evolution of the system to be determined primarily by the structure of the global magnetic fields with little sensitivity to the micro-physics of magnetic reconnection; and in a stratified atmosphere, we identify a novel mechanism for producing quasi-periodic behavior at the reconnection site behind a rising flux rope as a possible explanation of similar phenomena observed in solar and stellar flares.Comment: Submitted Feb 28, 2014 to, accepted Aug 14, 2014 by Astronomy & Astrophysics. 13 pages, 10 figures, 2 table

ASEAN states, their reservations to human rights treaties and the proposed ASEAN commission on women and children

This article was inspired by claims made by a number of participants at the Fifth Workshop on an ASEAN Regional Mechanism on Human Rights in Kuala Lumpur (2006) that because all ASEAN states were party to the Convention on the Rights of the Child and the Convention on the Elimination of Discrimination against Women, they shared common legal obligations and so the path was clear for moving forward with the Hanoi Action Plan's Commission on Women and Children. At that time, it was not clear that ASEAN would go any further than this commission. This article is therefore an examination of the law on reservations, but one that has at its core an examination of ASEAN states' reservations to the six main human rights treaties in light of Vienna Convention on the Law of Treaties. Analysis is situated in the on-going debate about reservations to human rights treaties, as well as assessment of the significance and impact of the ASEAN reservations in themselves, in relation to other state parties, on the proposed Commission on Women and Children, and on international law generally. Since this article was written, ASEAN adopted a new Charter for the organization, which, in Article 14, allows for the creation of a human rights body, to operate in accordance with terms of reference yet to be decided by the Foreign Ministers of ASEAN. The Commission on Women and Children has yet to be established. © 2008 by The Johns Hopkins University Press.published_or_final_versio

A Simple and Effective Method of Detecting Trichina in Sausage

Trichinosis is not a common disease in the United States on account of present day methods of handling meats and the rather universal habit of eating meat only after being well cooked. Occasionally, however, we find people partaking of raw or poorly cooked sausage. An outbreak of the disease resulting from the eating of raw summer sausage and involving five or six families and ten or more individuals occurred at Bridgewater, Iowa, last February. Several of the cases proved fatal

Interpretive Reproduction and Informal Music Learning in the Grade One Classroom

This study investigated informal learning practices in music education as a pedagogical approach within the primary classroom setting. It aims to explore and expand knowledge in the new field of informal music pedagogy through an investigation of its application with Grade One students (ages 5-7). Using the new sociology of childhood as an analytic tool, this study examines children as agentic beings within the structure of childhood, interpreting and reproducing childhood culture. It therefore places emphasis on the importance to primary music education of providing spaces within which children can experiment with and re/create peer musical cultures. Qualitative case-study methodology was used with two classes of Grade One students (n=35) in a Roman Catholic elementary school in Southwestern Ontario. Audio/visual data were collected and analyzed along with researcher-participant observation, teacher observation, field notes and semi-structured interviews. The researcher was a participant-observer and designed three informal learning units delivered by the teacher as part of the study. Data were collected on social and musical behaviours of children, musical skills achieved or emergent (pitch-matching, specific rhythms, etc.), and child and teacher comments on their experiences. Findings suggest that the integration of informal learning in the Grade One music classroom inspires creativity in students and motivates independent and collaborative learning. Expectations of students and teachers are challenged, shifted and adapted as they work collaboratively with flexibility towards new goals. Harwood & Marsh (2012) have drawn significant connections between children’s playground learning and informal music learning as researched by Green (2008). Drawing on this comparison assists in bringing primary students’ musical cultures into the classroom, as Green (2008) has successfully done with adolescent musical culture. Building on childhood culture that takes place through playground and out-of-school practices may result in an innovative pedagogical approach with the potential to revolutionize how music teaching and learning is interpreted in the primary music classroom. This could possibly include an expansion of philosophical perspectives relating to music education of younger pupils and allow broader possibilities for students and teachers to engage in new pedagogies, thereby helping to redefine primary music teacher discourse and practice through informal learning approaches